1. Field of the Invention
The present invention relates to an Express Card interface adapter. More particularly, the present invention relates to an Express Card interface adapter that allows connections with Express Card peripheral devices and a universal serial bus (USB) interface system.
2. Description of the Related Art
Aside from functional improvements in the North Bridge CPU and DRAM, rapid progress in information technologies also leads to the replacement of the 26-pin PCI socket with USB and PCI-Express interface socket. On one hand, there is a reduction in the pin number leading to a drop in the manufacturing cost of pins and a volume reduction in the externally plugged card. On the other hand, there is an increase in the transmission frequency and operating efficiency of electronic devices. Hence, how to set up external devices or adapter interfaces having USB and PCI-Express interface so that an efficient system operation is provided is much to be desired in the present day electronic industry.
Articles that described an external system or adapter system having a USB and PCI-Express interface include, for example, U.S. Pat. No. 6,141,719 submitted by Network Technologies, Inc. (Aurora, Ohio) with the title “USB selector switch”, U.S. Pat. No. 6,257,930 submitted by Advanced Connecteck Inc. (Hsintien, TW) with the title “USB electrical connector”, and U.S. Pat. No. 5,808,481 submitted by Intel Corporation (Santa Clara, Calif.) with the title “Output swing clamp for USB differential buffer”. All of these represent some form of improvements of the USB device from the old specifications.
To enhance the frequency bandwidth of interface and facilitate the operation and lower the production cost of the system, the PCMCIA Association has introduced a new Express Card standard in the year 2003. The new Express card standard deploys USB 2.0 and PCI-Express as an interface for linking with the system. Since a single card can have two interfaces and can support high-speed data transmission and hot plugging/unplugging operation, the new interface specification will have considerable development potential in the future.
Although the new Express Card standard allows the built-in USB or PCI-Express interface to facilitate operation and lower overall system cost, its application is still quite limited because the standard is out for a limited time only. Consequently, external devices or related peripheral devices having an Express Card interface can hardly be linked to systems of the previous generation having built-in USB or PCI-Express interface and can only be used in electronic equipment having similarly built-in Express Card interface socket. In other words, external devices or related peripheral products having the Express Card interface cannot be directly plugged into the most common USB or PCI-Express interface currently in use. This significantly reduces the applicability of the new standard interface.
Therefore, a system and its peripheral products having the new Express Card interface and yet can be directly used in all existing USB or PCI-Express interface is very much sought after by people in the electronic industry.